Dr. Margie Kahn is Director of Pelvic Floor Medicine and
Reconstructive Pelvic Surgery at the University of Texas Medical Branch
(UTMB) in Galveston. She received her medical degree from Tulane University,
in New Orleans, La., and is board certified in obstetrics and gynecology.
While completing her three-year Urogynecology Fellowship at St. George's
Hospital in London, Dr. Kahn received a two-year grant to study methods
of rectocele repair. She is a member of the International Continence Society,
the International Urogynecologic Association, and the American Urogynecologic
Association. Her papers have been published in peer-reviewed journals and
textbooks and she has reviewed papers on an ad-hoc basis for four professional
journals. She also serves on the editorial board of the Journal of Pelvic
Surgery.

Urge Incontinence Versus Stress Incontinence:
What's the Difference and Why is it Important?

"Listen to the patient; she's telling you what's wrong."

- (Paraphrasing) William Osler

When you complain to your doctor that you leak urine, s/he will try to distinguish between urge and
stress incontinence. She wants to treat your main complaint, even if you do
not have a name for it.

Urge incontinence is the loss of urine associated with an intense urge to urinate.
Although it may occur spontaneously, it may be preceded by certain provocative
activities such as putting the key into the lock of the front door, such as "key-in-lock" incontinence.
Examples of other such provocations are the sound of running water, showering,
washing the dishes, cold weather or changing position. Many women describe urine
loss that occurs with little or no warning -- that "when you gotta go, you gotta
go" feeling. Urge incontinence is often associated with urinary urgency, frequency
and nocturia, or urination at night. These are all symptoms of an overactive
bladder.

Although incontinence certainly causes emotional distress, stress incontinence
is defined differently. Stress incontinence is loss of urine without
an urge to void that is usually triggered by an activity causing an increase
in intra-abdominal pressure. This is the type of urinary loss caused by coughing,
sneezing, jumping, lifting or pushing a swing. It is often associated with exercise,
hitting a golf ball or a tennis ball, gymnastics, or high-impact aerobics.

Women with stress incontinence may urinate frequently, but this is done in
an attempt to keep the bladder empty, not because they have frequent urges to
void. At its worst, stress incontinence may occur with very small movements
such as rolling over in bed or standing up from a sitting position. For some
women these activities may also cause urges to void. That may confuse women
trying to distinguish between the two symptoms, but if the leakage episode is
associated with urinary urgency, the event is defined as an urge incontinent
leak.

Many women have episodes of both symptoms at different times. They have mixed
incontinence. For treatment, it is helpful to determine which symptom is the
most bothersome.

The bladder is a storage bag made mostly of a muscle called the "detrusor."
The normal bladder has the amazing capacity to hold increasing amounts of fluid
without increasing its pressure until it is very full (over a pint) or it is
time to void. That is when the detrusor muscle contracts from its normally relaxed
state, increasing the pressure within the bladder so it can empty its contents
through the urethra.

The urethra is the valve that closes the bladder. Its muscle is called the
urinary sphincter. The urethral sphincter is normally contracted and working
to prevent the loss of urine until it is time to void. Normal urethral sphincters
relax only at these socially acceptable times.

When Things Go Wrong

Overactive bladder and urge incontinence are most commonly associated with
an overactive detrusor muscle. This muscle squeezes at inappropriate times,
contracting the bladder. When this happens, sometimes squeezing the urethral
sphincter and pelvic floor muscles may hold back the leakage until the detrusor
muscle relaxes, but sometimes the contraction and the urge is too strong and
urethral sphincter reflexively opens, allowing the passage of urine.

Stress incontinence results from weak urethral sphincter muscles and associated
pelvic floor muscles, so that urinary leakage occurs with any sudden jarring
of the body. This external pressure is transmitted through the bladder as with
a sneeze, but the detrusor muscle itself does not contract. The stronger the
external force the more the urethral sphincter must work to prevent leakage.

Why Do Things Go Wrong?

Incontinence often occurs as a result of any number of reversible conditions.
The first thing that your doctor might do is to obtain a urine sample to analyze
and culture. Blood in the urine suggests infection, cancer, or a stone. Bacteria
and white blood cells are signs of infection. Uncontrolled diabetics may show
glucose in the urine. The frequent urination caused by diabetes is sometimes
the first symptom that brings a woman to the doctor.

If these reversible conditions are absent, it is difficult to know why women
develop urge incontinence. We know that the detrusor can grow bigger and overactive
in response to a urethral constriction, such as in men with prostrate trouble.
However, in women, the reasons are less clear. We do know the problem becomes
more common with age and after menopause with loss of estrogen. Stress incontinence
is thought to be due to weakness of the pelvic floor muscles from damage to
the nerves and muscles during childbirth, from chronic straining at stool, repeated
heavy lifting, from hereditary factors, and from connective tissue that is too
stretchy as found in those with hyper mobile joints.

What if I'm Not Sure What My Problem is, or Which Problem is Worse?

A urinary diary is very helpful for making you aware of what happens to you
on a daily basis. It also gives your doctor a window into your daily life. Normally,
you keep the diary for three days. In it you put the time of every void and
every leak, whether your urinary leak is accompanied by urgency or stress symptoms,
and what provoked the leak. The amount that you drink each day is also helpful.

What else might your doctor do?

After you void, your doctor might measure the amount of urine left in your
bladder. Called the post-void residual, this value can be determined by ultrasound
or catheterization. This is important information. If you never empty the last
8-10 ounces in your bladder, that doesn't leave much room for the fresh urine
that your kidneys are constantly producing!

If no potentially reversible conditions are found, your doctor may initiate
treatment without further testing.

What are the Differences in Treatment?

Many of the non-surgical, non-medicinal treatments for urinary incontinence
benefit both urge and stress incontinence. Bladder training and electrical stimulation
may be more beneficial for urge incontinence. Kegel exercises, vaginal cones,
and biofeedback may be more beneficial for stress incontinence.

Pessaries, vaginal devices that support the bladder neck, and urethral plugs
benefit only stress incontinence.

Drugs such as oxybutinin and tolterodine treat urge incontinence by relaxing
the detrusor muscle, allowing greater bladder volumes. Pseudoephedrine contracts
the urethral sphincter to prevent stress incontinence. Phenylpropanolamine was
used for this purpose, but has recently been taken off the market. There are
at least two drugs undergoing clinical trials for the treatment of stress incontinence,
but no drug is currently FDA approved for this indication.

Surgery specifically treats only stress incontinence. Because many incontinence
operations obstruct the urethra and bladder neck, surgery can worsen or even
cause urge incontinence. Women with mixed incontinence are less likely to be
cured by surgery than those with pure stress incontinence. Medication cures
about half of these women, allowing them to avoid surgery.

Sometimes your main complaint changes during the course of treatment. Open
communication between you and your doctor will help you determine what your
diagnosis is, and what treatment is right for you.